“The Big Three” for Diagnostic Error

Recently, a study was done to look at misdiagnosis and the harms it causes. It was published in the medical journal called Diagnosis, the official journal of the Society to Improve Diagnosis in Medicine (SIDM).¹ The study was led by Dr. David E. Newman-Toker, a Professor of Neurology at the Johns Hopkins University School of Medicine. Important findings from the paper were also presented at a Capitol Hill briefing that was sponsored by the SIDM, and funded through the Gordon and Betty Moore Foundation, in order to bring awareness and inspire healthcare-related changes when it comes to the serious harms of misdiagnosis.

Malpractice cases and misdiagnosis

The study identified “the Big Three” when it comes to misdiagnosis, and more specifically, the harms it causes. These Big Three included cancers, vascular events, and infections. These categories were determined to be major players involved in misdiagnosis-related harms after the researchers analyzed over 55,000 total malpractice claims from the years 2006-2015 within the Controlled Risk Insurance Company’s Comparative Benchmarking System. This database is thought to represent about 30% of all malpractice cases in the United States. Of the over 55,000 malpractice cases analyzed, close to 12,000 (just over 20%) were related to diagnostic error. Almost 7,400 of these diagnostic error-related cases were deemed severe, with an outcome of permanent disability or death.

The cost of misdiagnosis

Misdiagnoses related to the Big Three made up over 60% of all diagnostic error cases, and over two-thirds of all diagnostic error payouts. However, when looking specifically high severity cases, meaning cases that resulted in permanent disability or death, the Big Three made up almost 75% of these. This suggests that not only are the Big Three common in misdiagnosis situations, but they are also often associated with some of the most serious outcomes.

Cancers versus other conditions

Of the 75% of the Big Three-related cases deemed severe in relation to diagnostic error, nearly 38% were related to cancers. This was more than both vascular events and infections combined, making cancer a top player in misdiagnosis-related harms. Interestingly, although cancer-related misdiagnosis made up the majority of these cases, the actual incidence of cancer is significantly lower than for infection and vascular events. This means, although many more people have vascular events and infections, these are not the most common conditions related to misdiagnosis. This highlights the importance of cancer in relation to misdiagnosis and its related harms.

What are the Big Three?

Specifically, the researchers identified five conditions within each Big Three category that made up about half of all misdiagnosis-related malpractice cases. This means that 15 conditions (five from each category) represented 50% of all diagnostic error cases. For vascular events, some of these included heart attack and stroke, while infections included pneumonia and sepsis, among others. The top five cancers that were related to diagnostic error included:

1. Lung cancer
2. Colorectal cancer
3. Breast cancer
4. Melanoma
5. Prostate cancer

Where does melanoma misdiagnosis occur?

While infection and vascular-related diagnostic errors were most often found in the hospital or emergency room setting, cancer-related misdiagnosis events were most commonly reported in the outpatient or clinic setting. The researchers suggested that issues with continuous care during the sometimes slow and sneaky onset of some cancers may be the reason they are often misdiagnosed in the clinic. The long-term and potentially discontinuous care in clinics may also lead to poor follow-up when it comes to diagnostic testing, with important information falling through the cracks.

Inspiring change

The researchers and the SIDM are hoping to use this information to inspire change and targeted initiatives in specific settings to help reduce misdiagnosis and misdiagnosis-related harms. The team of researchers are working on two more follow-up studies to further investigate the true proportion of Big Three-related diagnostic errors in the population, and to find out more on the impact of these misdiagnoses.